Emergency workers are trying to stem the flow of burning red sludge that has engulfed three villages.
More than 100 people have been injured, suffering from burns and eye irritation caused by the lead and other highly corrosive elements contained in the sludge.
The spill is streaming from a burst waste reservoir at an aluminium plant and there are fears it may reach the river Danube, one of Europe's main waterways.
Al Jazeera's Zeina Awad reports.
